1. Monitoring For Ozone Donovan Rafferty Ecology Ron Cunningham Oregon DEQ Anthony Reneau Tanabyte Engineering A review for station operators

2. n The Air Monitoring Station n The Monitoring Equipment n Performing Quality Control Checks n Certifying Ozone Standards What we will cover

3. You will learn….. by making mistakes !

6. Installing Monitoring Equipment n Connecting sample tubing to the sample gas inlet fitting. n Connecting the primary power. n Connecting the recorder. n Connecting the phone line. n Connecting the temperature probe. n Installation of Teflon® filter. n Connecting the data logger.

7. The Monitoring Station

8. The Probe n Probe is made of Teflon®. n The residence time is critical. n EPA requires a sample residence time of less than 20 seconds. n At 2.0 LPM the maximum probe length should be less than 170 ft. n For 10 seconds the maximum probe length should be 84 ft.

10. When you arrive at the site….. n Survey the structure housing the equipment for weather leaks, safety, and security. n Perform routine maintenance. n If you find a problem, you are responsible for seeing it is corrected. n Record the actions that you took.

11. Monitoring Checklist The Analyzer n Check to see if the power is on. n Is the sample flow set to 2.0 LPM? n Is the selector switch in the “operate mode”? n Can you hear the solenoid valve cycling?

12. Environmental Controls for Monitoring Equipment n Instrument vibration (Never “stack instruments”) n Keep sunlight from “shining” on instruments. n Electrical voltage n Temperature n Security n Cleanliness

13. Standard Operating Procedures n Data collected using fully documented procedures have much higher credibility. n Developed using the CFR’s and technical assistance documents.

15. If you didn’t record it …… you didn’t do it.

16. Monitoring Checklist n Developed to help the first time operator or one that does it infrequently.

18. Quality Control Checks n Should be performed at least once every two weeks. n Inspection of the shelter and instruments. n Zero, Precision and Span Checks n Adjustments

19. Never perform a calibration check on days forecasted to be above 90° F. unless there appears to be a problem with the ozone analyzer. The current ozone standard is 80 ppb/eight hour average. Calibrations should never be performed when ozone values are elevated.

20. The Monitoring Equipment n Ozone analyzers must meet reference method or equivalent method specified by the EPA in Appendix D of 40 CFR Part 50. n Dasibi 1008PC

21. Dasibi Ozone Analyzers n Meet EPA designated equivalent method requirements when operated under the following conditions: u Concentration range of 0 -.5 ppm u Line voltage of 105 -125 vac u Temperature of 68°- 86° F n The analyzers must be operated and maintained according to the Operating and Maintenance Manual to conform to the EPA Designation requirements.

24. Think of the instrument as being divided into two components…….

25. The Analyzer (Photometer). Flow set to 2.0 LPM.

26. The Ozone Analyzer Technique n Based on the principle that ozone molecules absorb UV light (254 nanometers wavelength). n A column of air is illuminated at one end by an ultraviolet lamp. n The intensity of the lamp is measured at the opposite end by a detector. n The measurement is performed within the sample tubes (absorption tubes) of the analyzer.

28. Critical Components of an Ozone Analyzer (Photometer) n Solenoid valve n Ozone to oxygen converter n Absorption tubes n Sample pump n UV lamp source n Detector

29. Gas Valve: actuated by a solenoid

30. Ozone Scrubber

31. Scrubber Cartridge copper screens coated with manganese dioxide

32. n The MnO 2 catalyzes the reaction of ozone to diatomic oxygen. n The sample entering the absorption cell after passing through the filter is preserved intact except for the ozone.

33. The Sample Pump

34. UV Lamp with output concentrated at 253.7 nm where absorption of ozone is maximized

35. Detector: Measures the intensity of the lamp

36. The Measurement n Each measurement cycle is completed within 10 to 20 seconds. n Each measurement contains two half cycles.

37. The First Measurement Half-Cycle n Ambient air is directed by the analyzer’s solenoid valve to the scrubber where any ozone present is converted to oxygen. n The ozone-free sample is directed through the absorption tubes.

38. n The UV source lamp illuminates the sample and the transmitted intensity is measured by the detector. n The analyzer stores the intensity value.

39. Zero (reference) gas with the ozone “scrubbed” Sample The First Measurement Half Cycle Solenoid Scrubber Absorption Tubes

40. n The optical path length through the sample. n Transmittance of the sample at a wavelength of 253.7 nm n The temperature and pressure of the sample

41. The Second Measurement Half-Cycle n The sample is directed to the absorption tubes. n The UV source lamp illuminates the sample. n The detector measures the transmitted intensity.

42. The Second Measurement Half-Cycle n Any ozone present in the sample absorbs some UV light resulting in a lower intensity value as measured by the detector. n This value is is subtracted from the previously stored value and the resulting difference is the amount of ozone in the ambient sample.

43. Sample without the ozone “scrubbed” Sample The Second Measurement Half Cycle Solenoid Absorption Tubes

44. At the end of The Measurement Cycle n The measured result is displayed on the instrument as a concentration. n Presented as an electrical signal to the data logger and the strip chart recorder.

45. Since ozone is a highly reactive gas, accurate concentration of the gas cannot be made and stored for any length of time. To calibrate the analyzer, various concentrations of ozone must be made and measured on site. Specific protocols have been developed to generate and measure accurate concentrations of ozone on site.

46. The Ozone Transfer Standard n Think of as two instruments. n One half makes ozone. n The other half measures the sample. n Capable of generating and measuring accurate ozone concentrations.

47. Critical Components of an Ozone Transfer Standard n Zero air source. n Pump n Flow controller n Ozone generator n Manifold

48. Ozone transfer standard Ozone analyzer

49. Charcoal Column Used to absorb ozone in ambient air while performing a zero check

50. Generator Pump

51. Flow Controller for ozone generator (5 LPM)

52. Ozone Generator: produces ozone for calibration check

53. Ozone Generator with Ultraviolet (UV) Lamp

54. The Ozone Generator n Incoming air is subjected to ultraviolet radiation from a mercury vapor lamp. n The oxygen absorbs the UV light. n To dissipate the resulting gain in energy, the irradiated O 2 molecules split into two negatively charged oxygen atoms. n These atoms combine with unsplit oxygen to form O 3.

55. The Manifold n A specific volume of ozone or zero air enters the manifold. n The calibrator pulls a “sample” from the manifold. n The instrument that is being check also pulls a “sample” from the manifold. n The excess is allowed to vent.

56. 5 LPM 2 LPM for transfer standard The Manifold 2 LPM + excess to analyzer Capped

57. Ozone Scrubber Pump Flow Controller Ozone Generator Manifold To transfer standard capped Analyzer The Ozone Generator

58. Primary Standards and Transfer Standards n Are used to verify the accuracy of the instrument. n Primary Standards have the highest authority.

59. Primary Standards n Located at a central laboratory where it can remain stationary, protected from the physical shocks of transportation, operated by an experienced analyst under optimum conditions. n Serves as a common standard for all analyzers in a network. n Compared against other primary standards.

61. Compared against the Standard Reference Photometer (SRP)

63. Primary standards have the highest authority.

64. Participants of the SRP Program (SRP #4) n Arizona DEQ n Ecotech LTD (Australia) n California, Arizona,Hawaii, Utah n EMPAC (China) n Alaska,Oregon,Wash,Idaho n Lawrence Livermore Labs n National Park Service n Vandenberg AFB n Westinghouse Hanford Company

65. Ozone Transfer Standards n Transportable instrument n Contains an ozone analyzer and generator. n Together with the associated operational procedures, can accurately reproduce ozone concentration standards that are related to an authoritative primary or master standard.

66. Primary Standards Transfer Standards

69. Data Loggers and Telemetry n Before performing any calibration checks, disable the ozone channel. n Joan Kiely (360) 407-6839

70. Performing the Zero Check n Make sure the Transfer Standard has warmed up. n Set the ozone adjust thumbwheels to 000. n Set the ozone switch to the off position. n Turn the generator pump on.

71. Zero Check n Record the values using the form provided. n Check the data logger and recorder to make sure they are reading zero. n Allow @15 minutes to sample zero air. n Record the values using the ten count. n Remember to subtract the zero offset from all readings to obtain the true ozone reading.

72. The Precision Check n Turn the ozone lamp switch on. n Set the lamp to AUTO. n Set the thumbwheels to 090. n Allow 15 minutes after the trace plateaus. n Record the values using the ten count.

74. The Span Check n Set the thumb wheels to 400. n Allow for the trace to plateau. n Record the values using the ten count. n Multiply n Match output of analyzer to data logger and chart recorder

75. Determining the Precision of the Instrument n The precision of the instrument is the difference between the “actual” or true ozone value (measured by the Ozone Transfer Standard) and the “indicated value” (measured by the analyzer).

76. Indicated - Actual Actual X 100 = Percent Difference Percent Difference

77. Analyzer - Standard Standard X 100 = Percent Difference Percent Difference

79. After the Calibration Check n Record the sample chamber temperature. n Record the unadjusted sample frequency. n Record the sample chamber pressure. n Record the control frequency 50.000.

80. Performance Checks n Sample Flow Check n Span Check n Control Frequency Check n Sample Frequency Check

81. Sample Flow Check n Tap the flowmeter to make sure the float is not stuck. n Should read @ 2.0 L/min. n Adjust if less than 1.8 L/min or greater than 2.2 L/min. n Never lower than 1.5 or higher than 3.5 L/min

82. Span Check n Turn mode switch to SPAN. n Should read 30.8xx n Set in lab. Do not adjust. n If it does not read 30.8xx, contact David at the lab.

84. Control Frequency Check n Should always be 50.000 on the display n If not, contact David.

85. Sample Frequency Check n Should not be below 410 KHz. n Track the degradation. n Large drops indicate dirty optics. n Adjust frequency between 460 KHz and 410 KHz.

86. To adjust the sample frequency n Set mode selector switch to SAMP/TEMP with T/P off. n Loosen the dual screws on the Light Source Block. n Push lamp in to increase, pull out to decrease the lamp intensity, or rotated. Small movements needed. n Tighten screws when done.

88. Pressure Check n Check the analyzer pressure against a certified barometer.

89. 0.5-micronTeflon® Filter n Intalled before entering the analyzer. n Will not degrade the ozone concentration. n Change filters regularly.

90. The.5 micron teflon® filter holder Remember to change filter when dirty

91. Diagnostic LED

92. n 0 = No faults n 1 = Not used yet n 2 = Sample Frequency is not above 300 Khz, or is not below 480 Khz. n 3 = Control Frequency is not at 500 Khz. n 4 = Lamp heater voltage is incorrect. n 7 = CPU reset occurrence. n 8 = Displayed whenever any front panel switch not in the correct position for proper operation.

95. Patience is a Virtue n Allow yourself enough time. n How fast you can do it means nothing. n If you rush you are bound to make mistakes. n Mistakes usually cost lost data, time and money. n The best operators take their time, are methodical and thorough.

96. Before Leaving the Station……. n Record the results of the calibration check and any changes that were made to the instruments. n Make sure that the analyzer is running and that all the switches are in their correct positions. n Enable the data logger. n Make sure that the station is secured.

97. Before you leave…….. n Check to see if the power is on. n Is the sample flow set to 2.0 LPM? n Is the selector switch in the “operate mode”? n Can you hear the solenoid valve cycling? n Has channel 03 on the data logger been disabled?

98. Strip Charts n Before performing any calibration checks, annotate the strip chart. n Make your entry into the logbook. n Sean Lundblad (360) 407-6843

99. Quarterly Quality Assurance Audits n A Quality Assurance representative visits the site quarterly. n Challenges the station analyzer with concentrations generated by the QA transfer standard. n Checks for the accuracy of the analyzer. n Discusses issues that arise during the audit.

100. The Critical Criteria Table

101. The Operational Criteria Table

102. The Systematic Table

103. Data Validation Tables n Criticalprecision and accuracy n Operationalshelter temperature n Systematiccertified ozone standard or SRP comparison

104. Bad data… is worse than no data at all.

105. Maintaining Your Monitoring Equipment u Break to the Technical Assistance Lab. u Calibration Lab(360) 407-6030